Target the following repair scripts to the specific IP(s) of the nodes that are failing to upgrade and reboot:
sudo rm /etc/apt/trusted.gpg* -rf
sudo /usr/bin/apt-key adv –keyserver keyserver.ubuntu.com:80 –recv-keys 7EA0A9C3F273FCD8
sudo /usr/bin/apt-key adv –keyserver keyserver.ubuntu.com:80 –recv-keys 3B4FE6ACC0B21F32
sudo /usr/bin/curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add –
sudo /usr/bin/apt-get update -y
sudo reboot now
sudo mkdir -p /etc/apt/trusted.gpg.d